Respiratory rehabilitation: improvement of short- and long-term outcome.

Studies over the last 5–10 yrs have clearly demonstrated the benefits of rehabilitation programmes on chronic obstructive pulmonary disease (COPD) patients9 exercise capacity, quality of life, and utilisa-tion of healthcare resources. Despite these achievements , several unanswered questions need to be addressed to further improve the outcome of rehabilitation in COPD. The effects of exercise training on survival, the effectiveness of various modalities of exercise training and the maintenance of the effects in the long-term remain largely unknown. In the current issue of the European Respiratory Journal, the latter two of these issues are addressed. VOGIATZIS et al. [1] report on the feasibility of interval training as an alternative training modality for endurance training. Indeed, most training programmes in COPD rehabilitation are based on endurance training, which effectively means periods of sustained exercise for 20–30 min. High-intensity training is needed for an improvement in exercise performance [2], but severely obstructed patients with hypoxaemia and hyper-capnia or patients with severe muscle weakness, poorly tolerate such high intensities for longer periods of time [3]. Central restraints in addition to peripheral skeletal-muscle dysfunction might hamper endurance exercise training in these cases [4]. During interval training, short periods (30 s–2 min) of high-intensity exercise will stress the working muscle mass without being limited by central restraints evoking too many symptoms. The paper by VOGIATZIS et al. [1] demonstrates that interval training induces similar improvements in exercise performance and quality of life in comparison to endurance training. Importantly, symptoms of dyspnoea during the exercise sessions were significantly lower in the interval-training group. This might also improve compliance with exercise training programmes and thus, the effectiveness of this treatment. This study suggests that patients with more severely impaired physiological capabilities should be considered eligible for rehabilitation. However , only moderate physiological training effects, i.e. maximum oxygen consumption (V9O 2 max) did not improve in either group, were demonstrated. This was probably due to the low training frequency of only twice a week. This is below the threshold to observe clear physiological training responses, as indicated in the recommendations of the American College of Sports Medicine [5]. BROOKS et al. [6] dealt with the issue of long-term maintenance of the improvements after rehabilitation. It is well known that training effects are reversed in the long-term when exercise training is stopped [5]. This is true for healthy subjects and is also demonstrated in patients with COPD [7]. BROOKS …